Thermal transformations during thermal recovery of end-of-life composite carbon fiber beams from wind turbine blades

Abstract

The effects of thermal recovery technology on the composite carbon fiber beams from wind turbine blades were investigated. Nonisothermal thermogravimetric experiments performed under different atmospheres showed that the reaction activation energy were the smallest for N₂, and Δm was approximately 21.64 %. The activation energy was largest in air. The activation energies of the nonisothermal reactions at heating rates of 5, 10, and 15 °C/min in N₂ were 93.43, 116.95 and 128.86 kJ/mol, respectively. Higher heating rates led to more difficult reactions. The compositions of the products formed during isothermal pyrolysis at 600 °C were analyzed. CO₂ was the main component of gaseous products; and the remaining components were small combustible gases. The gas products accounted for 4.58 % of the total yield. The liquid tar product was approximately 21.28 %, featuring mostly aromatic substances containing arene rings, similar to phenol. The solid products accounted for approximately 74.14 % of the weight of the original reactant. The reaction mechanism was analyzed; the reaction predominantly involved the resin component of the composite, and the recovered carbon fibers remained essentially unchanged after the reaction. These results showed that it is feasible to recover carbon fibers from wind turbine blade composite carbon fiber beams by pyrolysis.