Abstract:
With large numbers of wind turbines being decommissioned, the environmental impact of decommissioned blades is becoming more severe. Wind turbine blades are composed of thermosetting resin matrix fiber-reinforced composites materials, which cannot be remelted or reshaped, posing challenges to resource recovery and utilization. Pyrolysis technology achieves the separation of inorganic fibers and organic resins by decomposing organic components under high temperature and oxygen free condition. Compared with mechanical recycling and chemical recycling, pyrolysis offers advantages such as large processing capacity, high value of recovered products, and high carbon emission reduction. This paper systematically reviews the material composition of wind turbine blades, pyrolysis recycling technologies, and characteristics of pyrolysis products. The effects of pyrolysis methods (fixed-bed, fluidized-bed, microwave, concentrated solar pyrolysis, vacuum pyrolysis), pyrolysis temperature, pyrolysis atmosphere (N
2, O
2, CO
2, water vapor, vacuum), and catalyst types (molecular sieve, metal oxides, modified biochar) on the three-phase product yields and liquid product composition from different wind turbine blade materials were reviewed. The results indicate that different pyrolysis methods exhibit distinct advantages in product distribution: fixed-bed pyrolysis favors the formation of solid products, fluidized-bed pyrolysis results in higher gas yields, while microwave and concentrated solar thermal pyrolysis excel in liquid product generation. Pyrolysis temperature plays a regulatory role in product distribution, with medium-to-low temperatures favoring the formation of phenolic compounds and high temperatures promoting the generation of aromatic hydrocarbons. The pyrolysis atmosphere can directionally optimize product composition; O
2 and water vapor atmospheres significantly increase the content of bisphenol A, whereas a CO
2 atmosphere has the opposite effect. The introduction of catalysts can markedly alter the composition of pyrolysis oil, with ZnCl
2-modified biochar achieving the highest phenol yield and Ga-modified ZSM-5 yielding the highest aromatic hydrocarbon content. This review provides a reference for optimizing the pyrolysis recovery process of decommissioned wind turbine blades and for the high-value utilization of pyrolysis products.