Plasma assisted oxidation of CFRC turbine blade scrap
Topic(s) : Special Sessions
Co-authors :
Dimitrios MARINIS (GREECE), Ergina FARSARI (GREECE), Eleftherios AMANATIDES (GREECE), Dimitrios MATARASAbstract :
The escalating demand for carbon fiber reinforced composites (CFRCs) underscores the need for effective recycling methods of those materials after the end of their life cycle. The widespread use of epoxy CFRCs, in aerospace, automotive industries, wind turbine blades, and structural components has brought a serious concern about their large amounts of waste, including leftover pieces, off-grade products and end-of-service-life components. Conventional disposal methods, such as landfill storage and incineration, lead to severe environmental pollution and waste of resources, often leading to regulatory bans in many countries. Therefore, chemical recycling emerges as a sustainable alternative, promising the recovery of high-quality carbon fibers through degradation of the resin matrix via selective cleavage of chemical bonds in the cross-link system.
To address these challenges, our study explores solvolysis, specifically wet oxidation techniques utilizing nitric acid. Nitric acid emerges as the most effective oxidant for solvolysis, in terms of recovered materials properties e.g. recovered fibers to preserve up to 98% of the original fiber strength have been reported. However, this method is time consuming while several environmental issues can arise. Therefore, in order to accelerate the degradation of CRFCs, our study combines traditional nitric acid solvolysis with nitrogen and argon plasma, aiming to enhance resin degradation.
The proposed plasma-enhanced solvolysis process involves a closed-loop system, utilizing a low-concentration nitric acid solution for materials pre-treatment and a high-concentration nitric acid which is exposed to plasma for the main treatment. In an attempt to minimize the NOx by- products that escape to atmosphere a wet scrubber is used.
The work focuses on high-quality fiber recovery and minimal treatment time. Wastes from wind turbine blades that have reached their end of life were treated. Electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) were used for recovered fibers physicochemical characterization, while ASTM D3379 standard mechanical tests took place, in order to evaluate the mechanical properties. Finally, the kinetics of the process and the energy consumption were examined. The experimental results showed that high quality materials can be retrieved in relatively short process times while the ratio between the volume of concentrated nitric acid and the composite mass can affect the efficiency of the process. Our results indicate that plasma assisted solvolysis can be a promising technology for recycling epoxy CFRCs, showcasing potential for large-scale applications.
To address these challenges, our study explores solvolysis, specifically wet oxidation techniques utilizing nitric acid. Nitric acid emerges as the most effective oxidant for solvolysis, in terms of recovered materials properties e.g. recovered fibers to preserve up to 98% of the original fiber strength have been reported. However, this method is time consuming while several environmental issues can arise. Therefore, in order to accelerate the degradation of CRFCs, our study combines traditional nitric acid solvolysis with nitrogen and argon plasma, aiming to enhance resin degradation.
The proposed plasma-enhanced solvolysis process involves a closed-loop system, utilizing a low-concentration nitric acid solution for materials pre-treatment and a high-concentration nitric acid which is exposed to plasma for the main treatment. In an attempt to minimize the NOx by- products that escape to atmosphere a wet scrubber is used.
The work focuses on high-quality fiber recovery and minimal treatment time. Wastes from wind turbine blades that have reached their end of life were treated. Electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) were used for recovered fibers physicochemical characterization, while ASTM D3379 standard mechanical tests took place, in order to evaluate the mechanical properties. Finally, the kinetics of the process and the energy consumption were examined. The experimental results showed that high quality materials can be retrieved in relatively short process times while the ratio between the volume of concentrated nitric acid and the composite mass can affect the efficiency of the process. Our results indicate that plasma assisted solvolysis can be a promising technology for recycling epoxy CFRCs, showcasing potential for large-scale applications.