Recycling and Disposal Cost Modelling of Carbon Fibre Reinforced Composites

Faculty Development Competitive Research Grant Program 2019-2021

Composite recycling is increasingly important owing to the rapidly increasing use of these materials many sectors such as aerospace, automotive and energy. Typical examples of the extensive applications of carbon fibre composites (CFC) are in both Airbus and Boeing civil aircraft families such as A350 XWB (52% of total mass CFC), A380 (25% CFC) and B787 (50% CFC). Rolls-Royce has also used composites as a vital component of aero-engines and the JSF propulsion system. These materials need to be disposed of in a cost effective, safe and environmentally responsible way at the end of their useful life. Product designers need to consider the costs associated with manufacturing and the end of life stage of such materials. They also need to understand the current methods of composites recycling and disposal and their impact on the end of life costs.
The land-filling of manufacturing waste or end of life composites is no longer a commercially viable option as various European directives (e.g. Council Directive, 1999/31/EC) are forcing manufacturers and suppliers to accept responsibility for recycling end of life wastes (Grant, 2018). It is already illegal to landfill composites waste in many EU countries. Furthermore, political and environmental pressures will force manufacturers to consider recycling composite materials more in the coming years (Halliwell, 2006).
Proven technologies for recycling thermoset composite materials can be classified as mechanical, thermal and chemical recycling (Pickering, 2006; Butterworth-Hayes, 2018). Mechanical recycling techniques involve the use of grinding techniques of all of the constituents of the original composite to comminute the scrap material and produce recyclate products in different size ranges suitable for reuse as fillers or partial reinforcement in new composite material (Pickering, 2006 and Wilson, 2003). Thermal processes are used to break the scrap down into materials and energy. Fluidised bed process has been used to recover high grade glass and carbon fibre reinforcement from scrap glass and carbon fibre reinforced composites (Pickering, 2000 and Yip et al, 2002). The thermal recycling processes have the ability to tolerate more contaminated scrap materials. Recycling stages of composites and any material from end-of-life components includes dealing with contamination, collecting, identifying, sorting and separating the scrap material.
Predicting costs of recycle and disposal of composite components which encompass environmental and logistics costs is a challenging research topic. The data related to the recycling and disposal of composites is far scarcer compared to that of metallic components. Knowledge about the cost drivers and level of investment required to recycle such materials is necessary at the design stage. To meet the challenges, aerospace designers are required to gain understanding of the major cost drivers of the disposal of composites. Furthermore there is a need to develop recycling and disposal cost models of various types of aircraft composite materials.

The fully integrated project will research, develop and exploit advanced composites, cost engineering and waste management tools and techniques for predicting the recycling, disposal and environmental costs of composites that will enhance Kazakhstan industry's capabilities in the areas of end-of-life of composites. The research results of this project will be also relevant for composites materials as used in other industries such as automotive and wind turbine.