KIER: "Electrification of Metal Heat Treatment Contributes to Carbon Reduction"

A technology that contributes to carbon reduction through the "electrification" of metal heat treatment processes has been developed.

The Korea Institute of Energy Research announced on December 11 that Dr. Hyukyung Lee's research team from the Energy Convergence System Research Division has developed a technology that enables the metal heat treatment process in the production of galvanized steel sheets-used in automobiles and home appliances-to be conducted solely with electricity, instead of fossil fuels.

(From left) Hyukyung Lee, Principal Researcher; Eunkyung Lee, Senior Research Fellow; Woonam Jung, Senior Researcher; Changbok Ko, Senior Research Fellow. Provided by Korea Institute of Energy Research

This technology can be widely applied to energy-intensive industries such as steelmaking, and is expected to help reduce carbon emissions generated during industrial processes.

Galvanized steel sheets are produced through a process called the Continuous Galvanizing Line (CGL), in which steel plates are continuously passed through molten zinc. During this process, the steel sheets undergo "annealing," where they are heated and cooled to make them easier to bend and process.

The problem is that when the heat for the annealing furnace is supplied by burning fossil fuels such as natural gas, large amounts of carbon dioxide and nitrogen oxides are inevitably emitted. In fact, it is estimated that carbon dioxide emissions from steelmaking processes, including zinc production, account for up to 15% of the nation's total emissions.

To address this, the research team replaced the burners in conventional combustion-type annealing furnaces with electric heating elements, developing a "carbon-free annealing system" that operates solely on electricity without fossil fuels.

The core of the system developed by the team lies in the furnace design technology. While maintaining the refractory structure and steel sheet transport mechanism of traditional combustion-type annealing furnaces, the team installed electric heating elements at both the top and bottom instead of burners. By precisely designing the distance between the heating elements and the steel sheets, they enabled rapid and uniform heating of the steel sheets with high-temperature radiant heat, while minimizing heat loss through the furnace walls.

Applying this system, they annealed steel sheets with a thickness of 0.49 mm at 750 degrees Celsius, and the color, structure, and mechanical properties of the steel sheets were maintained at levels equivalent to those produced by combustion-type annealing furnaces.

In contrast, emissions of carbon dioxide and nitrogen oxides were reduced by more than 98% compared to combustion-type systems. Through this, the research team demonstrated that, as long as the equipment design and operating conditions are properly set, productivity and quality of the steel sheets can be maintained while significantly reducing carbon emissions.

In particular, the electric annealing furnace can operate without the fuel and air supply systems, burners, and exhaust systems required in combustion-type furnaces, allowing equipment investment and installation size to be reduced by about 40% compared to traditional systems.

Furthermore, if operated with renewable electricity such as wind or solar power, it can be transformed into a truly "carbon-free heat treatment process," contributing to compliance with global environmental regulations.

Dr. Lee stated, "This demonstration is the world's first case to confirm that carbon-free heating can be achieved simply by replacing burners with electric heating elements. Moving forward, our team will expand this to an AI-based design and operation technology that automatically suggests the optimal arrangement of heating elements according to the width, thickness, and conveying speed of the steel sheets. We aim to establish an 'export-oriented carbon-free heating solution' that can be linked to commercial-scale demonstrations and exports for domestic steelmakers."

This content was produced with the assistance of AI translation services.