A systemic study for enhanced waste heat recovery and renewable energy integration towards decarbonizing the aluminium industry

The aluminium remelting industry relies on natural gas to transform recycled aluminium into aluminium feedstock, entailing significant atmospheric emissions. Hydric resources are also affected as they are used as sinks of waste heat from the casting process. Enhanced waste heat recovery and renewable energy integration may play an important role in decarbonizing the energy requirements of the aluminium production and increase the revenues of the industrial site. Using biomass to replace fossil fuel via thermal gasification may also help to decentralize energy supply and diversify the energy inputs to heavy industries traditionally dependent on natural gas. Carbon abatement units along with power-to-gas systems may also aid offsetting the seasonal availability and prices of electricity and fuel. Yet, due to the nature of the heat exchanging interfaces in aluminium plants, the energy integration is more challenging compared to conventional chemical plants. Thus, a systematic study is used to determine the most suitable options to deliver the energy requirements to an aluminium plant, without significantly impacting its operational feasibility, especially in scenarios of seasonal prices. In this way, the arrangement with minimum investment cost that meets the energy demands of the industrial aluminium remelting can be determined. As a result, better integration approaches may reduce the total energy consumption, whereas the CO2 emissions can be cut down to net zero compared to the conventional scenario.