Curtailing Unhealthy Impacts of Steel Production: DOE Earthshot Program

Steel is one of the world’s most useful and valuable materials, and while its fabrication process may not be at the top of most people’s minds, its production is among the most carbon-intensive manufacturing processes around. Steel accounts for roughly 7% of the world’s carbon dioxide emissions, part of a broader industrial sector that accounted for about 30% of the greenhouse gas emissions in the U.S. in 2021, according to the Environmental Protection Agency.

Researchers from The University of Texas at Austin are part of a multi-university team attempting to decarbonize manufacturing, and one of their first targets is steel production. L.L Raja and Tan Bui-Thanh, faculty members from the Cockrell School of Engineering’s Department of Aerospace Engineering and Engineering Mechanics, are leading modeling work on alternative steel production methods.

Bui-Thanh, who is also a core faculty member at the Oden Institute for Computational Engineering and Sciences at UT says steelmaking is one of the five most carbon-intensive industries accounting for more than 50% of US energy-related industrial carbon dioxide emissions.

“Steel production is a prime candidate for disruption because it’s such a significant contributor to carbon emissions,” said Raja, who is also affiliated faculty at the Oden Institute. “Those emissions trap heat from the sun, which causes global warming, leading to climate changes that are altering weather patterns and disrupting natural environmental processes.”

The research team will develop hydrogen-plasma-smelting-reduction technology to dramatically reduce carbon emissions during the steelmaking process. Raja and Bui-Thanh will develop models to understand the complex phenomena that contribute to the plasma forming and plasma interaction with the iron ore for steelmaking and process data from the models and experiments.

Though the to-be-developed mathematical models and their high-fidelity simulations are necessary for the understanding of iron production, they will be too computationally extensive for design, control, and optimization tasks. This is where Bui-Thanh comes in via his “expertise on fast and accurate deep learning surrogate models, and real-time inverse problems and uncertainty quantification (UQ) capabilities comes into the picture.” 

The research is part of the U.S. Department of Energy’s Earthshots program. The team, which is led by Arizona State University, received $5 million from DOE to pursue this work under the Industrial Heat Shot initiative, one of seven areas included in the program. UT Austin received $1.1 million for their portion of the research.

The work is also part of the larger Electrified Processes for Industry without Carbon group, or EPIXC, a multi-institution effort.

The goals of EPIXC include eliminating carbon emissions by developing the technologies and workforce required to replace fossil fuel-based heating with electric power sources, as well as significant decarbonization of industrial processes using clean energy sources. UT is one of the primary institutions in EPIXC, behind Arizona State University, which is leading the initiative.

The team’s big challenge in this new work? Finding a clean, energy-efficient way to make steel with fewer impurities.

It’s possible to use hydrogen arc plasma to replace carbon-emitting heat sources or to use the same arc to achieve iron ore reduction to produce steel without emitting carbon dioxide. Further the hydrogen arc plasma process can be controlled to prevent the formation of impurities called “gangue,” which can render steel useless for many applications by damaging its structural integrity.

Hydrogen arc plasma smelting reduction of iron ore is only a concept at this point, according to the team’s project description. However, it is a promising tool to develop for dramatically reducing carbon emissions from steel production while expanding the variety of usable iron ore.

“There are several challenges that we will face and seek to address. The most challenging one is the extremely harsh environment presented by high-power atmospheric arcs that make it nearly impossible to diagnose arc structure and its properties directly within an electric arc furnace (EAF) environment.  Hence, very little is understood of the plasma dynamics, fluid mechanics, heat transfer and plasma chemistry in an EAF,” said Bui-Thanh. According to Bui-Thanh, the researchers anticipate that the range of time- and length-scales and variety of physical processes that need to be considered for the full-fidelity model can only be addressed through novel high-performance computing approaches implemented on upcoming exascale computing hardware. Resources at the Texas Advanced Computing Center (TACC) resources will be of critical importance to not only to test but also to produce results for our project.

The project timeline has three main thrusts: Arc Discharge Dynamics and Gas-Phase Chemistry, Ore melting, reduction and melt pool dynamics, and Materials characterization. Thrust 1 starts from year one: one third of if will be finished in year 2, and the last 2/3 will be finished in year three. Thrust 2 is planned to be completed in the first two year. Thrust 3 starts from years two and end in year three.

The researchers hope the scientific insights and theories arising from the project will enable steel makers to design and develop both technically and economically viable plasma reactors that make carbon-free steelmaking possible.

Bui-Thanh says as the world moves towards carbon neutral, this can only be good for the well-being of Earth and for the well-being of the next generations. “I feel responsible and am committed to be part of this critical mission on various fronts. In fact, for the past seven years, I have been conducting research on clean energy via nuclear fusion in collaboration with other universities and national lab. In addition, I am currently collaborating with a US company on the development of safe power control of hybrid electric engines. As a result, I was very happy to accept the Prof. Raja's invitation to be part of the team.”

Story adapted from the Cockrell School of Engineering’s Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin.