Having made major strides in reducing greenhouse gas (GHG) emissions, U.S. metal producers—particularly those in the steel and aluminum industries—are reaching out to researchers at private companies as well as universities to provide the inventive thinking and technological know-how to significantly shrink their carbon footprint. While the ultimate objective is developing a breakthrough technology to tame GHG emission, evolutionary interim approaches delivering steady improvements would help bridge the GHG gap until step-change technologies are commercialized
While much of this research is being funded by Washington through such initiatives as the Energy Department's Industrial Technologies Program (ITP), other research is being underwritten either by industry trade associations like the American Iron and Steel Institute (AISI) or by individual companies.
The main driver for research to date has been cost-reduction efforts keyed to cutting energy consumption, which in turn would reduce emissions, according to Harry S. Kurek, senior engineer for the End Use Solutions Group of the Gas Technology Institute (GTI), a Des Plaines, Ill.-based not-for-profit energy research and development organization.
That's because there aren't yet incentives to make tremendous efforts to reduce GHG emissions—at least not on a scale of those aimed at reducing energy consumption, said Arvind Thekdi, president of E3M Inc., North Potomac, Md. "The time will come when North America, like the European industry, will start giving a dollar value to GHG reduction, but an economic mechanism is not there yet."
The AISI is working with the Energy Department on longer-term research, called the Carbon Dioxide Breakthrough Program, to pioneer a next-generation iron and steelmaking technology. While the program, if successful, will dramatically reduce or eliminate carbon dioxide emissions from the steelmaking process, realization of the program's potential is thought to be 15 to 20 years away from commercialization.
One project involves research at the Massachusetts Institute of Technology for the production of iron by molten oxide electrolysis, an electrical process that generates no carbon dioxide gases other than those created producing the electricity in the first place. Molten oxide electrolysis is an extreme form of molten salt electrolysis, a technology that has been used to produce large volumes of metal, including aluminum, magnesium, lithium and rare earths. But unlike the molten salt technologies, it uses carbon-free anodes and wouldn't produce any carbon or carbon dioxide—only oxygen.
A project at the University of Utah, meanwhile, is focused on producing iron from iron ore through hydrogen flash smelting. The approach uses hydrogen—as opposed to carbon, whether coal or coke—as fuel, eliminating the production of carbon dioxide.
Several interim projects also are being researched by both the steel and aluminum industries, many through the Energy Department's ITP.
Kurek is currently working in cooperation with the AISI and the Energy Department on a project to evaluate thermochemical recuperation, which he said is a more-efficient waste-heat recovery technology. The objective is to achieve a 30-percent reduction in both fuel and carbon dioxide emissions, as well as a considerable reduction of nitrous oxide emissions, vs. conventional waste-heat recovery methods.
"This is not a new idea. It was originally conceived about 25 years ago at GTI, but natural gas was moderately priced at that time," narrowing the cost advantage of the technology, which is slightly more expensive than conventional waste-heat recovery methods, Kurek said. But the economics turned around when natural gas prices peaked prior to the current economic downturn.
E3M is conducting another steel-related ITP project involving a next-generation heating system for scale-free, or reduced-scale, steel reheating. While focusing mainly on reducing energy consumption, the system would have the attendant benefit of reducing GHG emissions, including carbon dioxide and nitrous oxide, Thekdi said.
Also under the ITP, the University of Illinois-Urbana, in collaboration with the Lawrence Livermore National Laboratory, is working on developing a three-dimensional multi-scale model of the aluminum hot-rolling process with an eye on reducing edge cracking and rolling surface defects, as well as scrap generation.
Currently, the recovery rate from the production of aluminum plate is only 82 percent, which means that there is an 18-percent loss, said Armand Beaudoin, a professor at the university and the lead researcher for the project. The model under development is expected to help reduce edge cracking and rolling defects by 50 percent, resulting in an annual energy savings of 1.27 trillion British thermal units and a cost savings of $126 million. It also could cut emissions of sulfur oxide, nitrogen oxide, carbon dioxide, particulate and volatile organic compounds. Commercialization of the model is expected to begin in early to mid-2010.
Meanwhile, the Natural Resources Research Institute at the University of Minnesota-Duluth is researching a next-generation metallic iron nodule, or nugget, technology in cooperation with the Energy Department's ITP and Nucor Corp.'s Nu-Iron Technologies LLC unit. The process uses pure oxygen rather than a mixture of oxygen and nitrogen, and could result in a 30-percent reduction in carbon dioxide and other GHG emissions.