Exploring recycling of composites using High-Voltage Fragmentation
Topic(s) : Special Sessions
Co-authors :
Marco DIANI (ITALY), Shravan TORVI (ITALY), Marcello COLLEDANIAbstract :
The escalating demand for renewable energy, particularly wind power, has led to a surge in wind turbine installations across Europe. However, the impelling challenge of effectively treating End-of-Life (EoL) wind turbine blades, primarily composed of glass fiber reinforced plastics (GFRP), needs innovative recycling solutions. In addition, the usage of these materials is constantly increasing in several other sectors as marine, automotive, construction and sports equipment.
Currently, EoL composite products are recycled through mechanical, thermal or chemical processes. The first ones are able to obtain particles composed of both reinforcement and matrix to be directly reinserted in new products, the second and the third ones aim at liberating the fibers from the resin. While mechanical processes are at quite high TRL, pyrolysis and solvolysis requires more research. For this reason, composite materials are often sent to landfill, where possible, or inserted in processes with low added value (as cement co-processing). In addition, conventional methods such as mechanical, thermal, and chemical processes face limitations in preserving mechanical properties and cost-effectiveness when recycling composite materials.
This work delves into the current challenges associated with these methods and introduces an alternative approach using High-Voltage Fragmentation (HVF), an advanced technology generating localized shockwaves through electric discharges. The procedure is based on the concept of electrodynamic fragmentation; a plasma channel arc is created between the two electrodes during current ramp-up at a time below 500 ns. Since solids have a lower dielectric breakdown strength than water, this plasma channel is concentrated on the solid sample that is being treated. This results in pressures between 10^9Pa and 10^10Pa and temperatures of around 10^4K, which causes localized shock waves to form inside the solid sample. The weak points at the sample's phase boundaries are the focus of these shock waves as they travel through the solid. As a result, different materials fracture or delaminate along the phase boundaries, facilitating their liberation.
The experimental investigation carried on in this work focuses on some of the key parameters of this process and analysing different composite materials. Results indicate that HVF not only provides controlled shredding but also yields clean fibers. The technology shows promise for addressing the pressing issue of recycling EoL wind turbine blades, demonstrating effective impurity liberation and GFRP recycling.
This study sets the stage for further exploration and potential integration of HVF into the recycling landscape, contributing to the sustainability of the wind energy sector and promoting high-quality material reuse in demand-driven applications.
Currently, EoL composite products are recycled through mechanical, thermal or chemical processes. The first ones are able to obtain particles composed of both reinforcement and matrix to be directly reinserted in new products, the second and the third ones aim at liberating the fibers from the resin. While mechanical processes are at quite high TRL, pyrolysis and solvolysis requires more research. For this reason, composite materials are often sent to landfill, where possible, or inserted in processes with low added value (as cement co-processing). In addition, conventional methods such as mechanical, thermal, and chemical processes face limitations in preserving mechanical properties and cost-effectiveness when recycling composite materials.
This work delves into the current challenges associated with these methods and introduces an alternative approach using High-Voltage Fragmentation (HVF), an advanced technology generating localized shockwaves through electric discharges. The procedure is based on the concept of electrodynamic fragmentation; a plasma channel arc is created between the two electrodes during current ramp-up at a time below 500 ns. Since solids have a lower dielectric breakdown strength than water, this plasma channel is concentrated on the solid sample that is being treated. This results in pressures between 10^9Pa and 10^10Pa and temperatures of around 10^4K, which causes localized shock waves to form inside the solid sample. The weak points at the sample's phase boundaries are the focus of these shock waves as they travel through the solid. As a result, different materials fracture or delaminate along the phase boundaries, facilitating their liberation.
The experimental investigation carried on in this work focuses on some of the key parameters of this process and analysing different composite materials. Results indicate that HVF not only provides controlled shredding but also yields clean fibers. The technology shows promise for addressing the pressing issue of recycling EoL wind turbine blades, demonstrating effective impurity liberation and GFRP recycling.
This study sets the stage for further exploration and potential integration of HVF into the recycling landscape, contributing to the sustainability of the wind energy sector and promoting high-quality material reuse in demand-driven applications.