Study on the recycling of waste wind turbine blades

Abstract

The pyrolysis process of waste wind turbine blades in the coal-fired flue gas was studied. The effects of pyrolysis temperature, pyrolysis time, flue gas composition and heating mode on the pyrolysis product were investigated, and the pyrolysis mechanism was also analyzed. Finally, the industrial implementation scheme of pyrolysis process in coal-fired power plants was formulated. The results showed that the matrix resin of wind turbine blades could be carbonized and then oxidized by direct heating with the flue gas. A clean glass fiber was finally obtained to recycle. When the blade was pyrolyzed at 420–450 ℃ for 5–6 h, the purity of recycled fiber was above 99 % and its tensile strength decrease was less than 10 % compared with the original fiber. During the pyrolysis process, the concentration of SO2 in flue gas had little effect on the quality of recycled fiber because of its nonreactivity with SiO2. With the increase of pyrolysis temperature, the purity of recycled fiber increased while its tensile strength decreased. In coal-fired power plants, a small fraction of flue gas was pumped from the tail flue of boiler by a fan. The flue gas after dust removal was sent to a recovery furnace, where the blade was pyrolyzed. The tail gas was transported to the boiler furnace for complete combustion and then purified by the existing pollutant purification devices in the power plant. According to the above scheme, the recycling of waste wind turbine blades in coal-fired power plants could be readily realized by equipping a duster, a recovery furnace and a fan.