VALORISING THERMAL RECYCLING PROCESSES OF FIBREREINFORCED COMPOSITES USING ORGANIC RANKINE CYCLES FOR COMBINED HEAT AND POWER APPLICATIONS

Abstract

Recycling is one of the most challenging issues in many different sectors, which can bring both significant economic and environmental benefits. Hence, recycling is one of the few domains in that economic interests are in line with diminishing environmental concerns. Among the feasible and profitable recyclable materials, fibre-reinforced polymers (FRPs) are at the early stages of technology readiness with end-of-life FRP material projected to increase significantly in the coming years. Therefore, the economic and environmental impacts of FRP recycling plants should be investigated to develop a reliable business case to support the development of a circular economy for these materials. To this end, the recycling process should be robustly designed, optimised, and integrated with energy systems to maximise economic and energy-saving benefits. In this work, an FRP thermal recycling plant coupled with a 30 kWel/175 kWth organic Rankine cycle (ORC) system for combined heat and power (CHP) is studied. The environmental benefits of this integrated recycling-energy system are presented in terms of net CO2 and operational costs. Results show that the integration with at least 50 residential apartments can significantly improve the economic and environmental indicators compared to the separate recycling plant and buildings being supplied by the electricity and natural gas (NG) grids. These indicators are identified by comparing the direct and indirect CO2 emission and operational costs of the recycling plant coupled with the ORC-CHP system with those generated by stand-alone systems producing virgin fibres, supplying domestic electric demand using the electric grid, and domestic space heating using the NG grid.