The Effect of Reduced Flue Gas Suctioning on Superstructure and Gas Temperatures

Reducing CO₂ emissions from aluminum smelters is of great interest to reach the goal of carbon neutrality. One possible approach is to implement carbon capture and sequestration techniques (CCS). This is already being done within the geothermal sector in Iceland, where captured CO₂ is sequestered through the Carbfix method of mineralization. Under the current smelter operation, the CO₂ concentration in the exhaust gas is below 1%, which is too low for conventional up-concentration technology, but by adjusting the draft rate, the concentration can increase to the required 4% or higher. In order to determine the feasibility of retrofitting this method into existing smelters, a CFD model has been developed to predict the effects that the draft rate modifications would cause within the system. In this paper, the results from CFD modeling of the flue gas and superstructure of the cell are used to predict changes in flow and thermal conditions. Outlet temperature values are determined for the air passing through the system as well as the surface temperatures of the anode cover material (ACM), hood cover, and anode rods.