Comparative LCA Analysis of Selected Recycling Methods for Carbon Fibers and Socio-Economic Analysis

Carbon fiber is essential in many industries. Since primary production is highly energy-intensive, recycling technologies are being sought. A goal of the research was to develop at a laboratory scale a chemical recycling method aimed at recovering carbon fiber. Two variants of the method have been established and environmentally compared with a primary production version. Methods: The life cycle assessment methodology has been used to assess and quantify the environmental impacts. The cradle to gate analysis was performed with the functional unit defined as a production of 1 kg of carbon fiber. Results: The best environmental option turned out to be a developed chemical recycling technology named Scenario 1. It is a solvolysis performed using an ambient-pressure-operated batch reactor connected to a reflux condenser and an inert gas supply tank, using an ethylene glycol and potassium hydroxide solution. The worst case appeared to be the second variant of the chemical recycling, named Scenario 2 (plasma-enhanced nitric acid solvolysis). Conclusions: In Scenario 1, a production of the ethylene glycol was recognized as a key environmental driver, while in Scenarios 2 and 3 the energy-related impact was the most influential.