The push to decarbonize industrial processes has prompted researchers in South Korea to develop and test an electrically heated continuous annealing furnace for the steel industry. The heat treatment technology was designed to replace fossil fuels with electricity in the metal heat treatment process used in galvanized steel-strip production for automobiles and household appliances.

The carbon-free annealing system operates solely on electricity by replacing the burners of conventional combustion-based annealing furnaces with electric heating elements. When tested under conditions replicating those of commercial production processes and applied to anneal steel-strips with a thickness of 0.49 millimeters at 750° C, the technology successfully reduced concentrations of carbon dioxide and nitrogen oxides in exhaust gases by more than 98%.

The system designed by researchers from Korea Institute of Energy Research, Korea University, SAMWOOECO Co. Ltd. and University of Science and Technology retains the refractory structure and steel-strip conveying mechanism of conventional combustion-based annealing furnaces. However, burners are replaced with electric heating elements installed on both the upper and lower sections of the furnace. By precisely configuring the distance between the heating elements and the steel-strip, rapid and uniform heating is provided through high-temperature radiant heat while minimizing heat loss to the furnace walls.

The electric annealing furnace described in Applied Thermal Engineering can operate without the fuel and air supply systems, burners and exhaust systems required for conventional combustion-based furnaces, reducing capital investment costs and installation footprint by approximately 40%. When powered by wind or solar energy, the system can deliver a truly carbon-free heat treatment process, making it highly effective in addressing global environmental regulations.