Engineering Sustainability of Mechanical Recycling on Carbon Fiber Composite Materials

Abstract

The high demand for carbon composite in many industries results in an increase in amount of required embodied energy to manufacture carbon composites. In order to save the energy consumption, recycling technologies are being developed. The purpose of this research is to analyze and estimate the specific energy consumption and mechanical recycling method, specifically using a ball mill with an air-classifier, which is not yet widely applied. The milling process is the most important step in recycling composites. The input energy requirement on milling process was theoretically calculated based on industrial scale (18ftx22ft over flow ball mill). The input energy consumption was calculated based on different feed and product sizes. It was assumed that the recycling processing rate was 2100 ton/year. The specific energy for recycling Carbon Fiber Reinforced Plastic was significantly less than the embodied energy of virgin CFRP. Although the energy consumption depends on the form of recycling CFRPs, the energy difference between virgin CFRP and recycled CFRP can be huge amount of energy savings. This result also brings environmental benefit by utilizing carbon waste with relatively low milling consumption in mechanical recycling. This research can also provide a further direction to model a closed loop of the overall recycling process.