Development of a medium-high temperature waste heat recovery hybrid thermal energy storage layout, based on red mud, a disregarded and potentially hazardous solid waste of the aluminium industry.

ended

As per an EU estimate, the industrial sector accounts for 27% of the overall energy consumption and for the generation of 30% heat-related CO2 emissions. Industrial thermal processes account for 70 % of the energy demand, which translates to 20.8% of the entire EU energy demand. Waste heat recovery (WHR) is, thus, one of the next frontiers for energy-intensive industries. Thermal energy storage (TES) is a promising alternative to currently available WHR technologies, particularly for medium-high temperature settings. Latent heat storage, centred on the ability of a material, commonly referred to as the phase change material (PCM), to absorb/release heat isothermally during its transition from one state to another, faces several performance issues inherent to the material’s properties. Encapsulating PCMs in solid matrices, consisting of refractory materials, has been found to resolve most of these issues. These new materials can be used to store both sensible and latent heat (hybrid TES) potentially outperforming current TES systems. The properties of red mud (RM), a currently disregarded and potentially hazardous waste of the aluminium industry, make it an ideal candidate for PCM encapsulation. REDTHERM aims to scale up the recently discovered, by the researcher, red mud-molten salt material and demonstrate, for the first time, its performance in a novel medium-high temperature WHR layout using real industrial settings. In this way it can promote a novel and tangible business case of industrial symbiosis (circular economy) in which the waste product of the aluminium industry (RM) is valorised as a key component for medium-high temperature WHR systems to increase energy efficiency and decrease the carbon footprint of foundation industries with relevant interest (steel, cement, casting etc. This timely project can substantially contribute towards the EU’s 2050 sustainability agenda, while in parallel expanding the science of the promising field of hybrid-TES.