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July 1, 2011

Good Results, Expect Better

The North American steel industry has done a world-class job of reducing harmful emissions. Emerging technologies will help steelmakers do even better—a lot better.

The North American steel industry has seen the brighter, lower-carbon future, and it appears to be attainable. Eventually.

The next generation of steel manufacturing may be significantly more energy-efficient, with even lower emissions than what has already been attained. It is, in fact, in development at various research institutions around the country. Unfortunately, says a U.S. Department of Energy (DOE) report released in March, and Forward's own update, the most promising new technologies are all at least a decade away from commercial use.

The next generation of steel manufacturing may be significantly more energy-efficient, with even lower emissions than what has already been attained. It is, in fact, in development at various research institutions around the country. Unfortunately, says a U.S. Department of Energy (DOE) report released in March, and Forward's own update, the most promising new technologies are all at least a decade away from commercial use.

The report, by Christopher L. Weber of Carnegie Mellon University and Mauricio Justiniano of Energetics Inc., offers a generally positive picture for an industry that faces increasing regulatory pressure to reduce its carbon footprint.

Although far cleaner in greenhouse gas emissions than either the electric power or oil refining industries, steel still accounts for 8% of all of carbon dioxide from U.S. industries, more than 2% of the total from all sources.

A long-term production shift within the steel industry to electric arc furnaces from basic oxygen furnaces, as well as other production improvements, have made the United States “the most energy-efficient global steel producer,” the DOE report says. Still, the industry “must make additional progress to achieve system-wide improvements.”

American steelmakers were quick to praise the report because of the long-running struggle with the U.S. Environmental Protection Agency (EPA), which is now implementing new greenhouse-gas reduction rules that ultimately may require major reductions in industry emissions.

Beginning in July, large smokestack factories—including steel manufacturers—must report their greenhouse gas emissions levels to EPA, and new or expanded facilities must undergo a rigorous new permitting process. The reporting requirement applies to factories that emit 100,000 or more metric tons of carbon dioxide annually or expanded ones that emit 75,000—facilities that account for 70% of the greenhouse gases emitted in the United States, EPA says. They include most steel plants, which, at current rates, emit about a ton of CO2 for every ton of steel produced. That's down from 2.2 tons emitted per ton of steel produced in 1990.

EPA is also requiring industries to show that they employ the “best available control technology” to reduce greenhouse gases. That's a sticking point. The American Iron and Steel Institute (AISI), which represents 24 North American steelmakers and 140 suppliers and customers of the steel industry, argues, for example, that the best available technology to increase energy efficiency and reduce greenhouse gases is already widely employed by steel manufacturers.

“There's no more juice in that orange,” says Lawrence Kavanaugh, president of AISI's Steel Market Development Institute, with support from the DOE report. Technologies used to reach this point have included scrap metal recycling in electric arc furnaces and low-carbon, direct-reduced iron to eliminate coking coal from the steel manufacturing process.

To do better, DOE says, breakthrough technologies are required.

“The U.S. steel industry has almost fully achieved the energy efficiency and carbon reductions that can be obtained using today's best available technologies,” the DOE report concludes. Further progress will require “additional breakthrough steelmaking technologies and processes.”

Is That Good Enough?

The evidence suggests that EPA doesn't plan to accept this conclusion. Less than a month after the DOE acknowledged the industry's progress, the Weber-Justiniano report, which was available on the DOE website, suddenly disappeared.

A DOE spokeswoman said the report was removed from public view because the department “is in the process of updating its steel report with additional information.” Neither Weber nor Justiniano, the authors, would comment. But a source familiar with the DOE process said the update is a policy matter; i.e., the administration found the DOE report inconvenient at a time when EPA is tightening the screws on industrial metals.

Canadian mills may face similar regulatory action, by both federal and provincial governments, says Ron Watkins, president of the Canadian Steel Producers Association. The federal government is discussing possible new regulations, though the administration of recently re-elected Prime Minister Stephen Harper has been slow to act, Canadian environmentalists say. During his election campaign, Harper criticized a proposed cap-and-trade program as a potential contributor to high gasoline prices (confusing the plan with a carbon tax, opposition leaders said).

Meanwhile, an annual index of progress made by the top 60 greenhouse gas emitters in the world, the Climate Change Performance Index, recently placed Canada fourth from the bottom.

Under the current federal approach, Environment Canada, the nation's version of EPA, establishes emissions standards by industrial sector. So far, says P.J. Partington, climate change technical and policy analyst for the environmental think tank The Pembina Institute, the government has drafted regulations only for the power industry, to be implemented by 2015.

“It's not a comprehensive policy,” he said. “It's unclear when and where they'll be acting.”

With little action at the federal level, provincial governments are seizing the initiative. The province of Ontario, where 70% of Canada's steel industry is located, along with Québec, Manitoba and British Columbia, have enacted their own, province-imposed cap-and-trade systems. The new market-driven program in those four provinces goes into effect Jan. 1, 2012. Industrial plants will be invited to buy emissions permits from the provincial governments (and eventually seven western U.S. states, all of them signatories to the so-called Western Climate Initiative). If factories don't meet government-imposed caps on emissions, they can buy permits from other plants or pay fines to the regional governments.

New Technology

Watkins says Canadian steelmakers are prepared. Canadian mills, like their U.S. counterparts, have already made significant environmental improvements. Since 1990, Canadian steelmakers have increased their energy efficiency by 26% and reduced greenhouse gas emissions by 17% (somewhat behind U.S. steelmakers, which increased energy efficiency by 30% during the same period and reduced greenhouse gas emissions by 35%).

Technological advances are in the works both in the United States and abroad. Some have come from collaborative research and development efforts, like the Technology Roadmap Program, a joint Department of Energy and AISI program that funneled $38 million into researching energy efficiency and environmental improvement. Those funds ran out in 2008.

The big question for both the United States and Canada is when meaningful breakthroughs will be available to steelmakers. DOE suggests that few of the ideas will have an impact until the 2020s.

Because steelmakers have developed techniques to cull process gases, researchers have focused on carbon capture and sequestration (CCS)—that is, separating the prime greenhouse gas produced in steelmaking, carbon dioxide, and storing it where it won't harm the environment, like under the sea or in abandoned mine shafts.

Researchers have experimented with techniques to combine carbon dioxide with minerals to form stable materials or to capture it during the iron-reduction or steelmaking processes. EPA contends that CCS is one greenhouse gas-reducing technology that should be considered “available” to the steel industry, though it acknowledges that technology is not now economically viable.

Setting a Standard

The problem is that “EPA opens the door to legal challenges by other parties in the future that allege CCS is a viable control technology that should be mandated in particular uses,” says AISI president and CEO Thomas J. Gibson. EPA responds that, so far, new regulations only require steelmakers to report carbon dioxide levels. EPA has not set a date for factories to actually reduce those levels; the most recent rule says only that greenhouse gas data will be used to “inform future policy decisions.”

Whether the technology is legally available or not, CCS research receives little support from U.S. funders.

A few years ago at the Missouri University of Science and Technology, researchers combined “off-gas” from steelmaking—the mixture of gases left over after the process is complete—with slag, a steel by-product laced with minerals that react with CO2, to form a stable end product. It's a reaction that occurs normally at steelmaking plants, with little notice, principal researcher Kent Peaslee says. At operating steel mills, slag from blast furnaces is typically aged in outdoor environments, where some CO2 from the air combines with it to form carbonates.

“Our idea was to process [the slag] in a way to get a much higher percentage of CO2 collection,” Peaslee says.

Researchers used both a slurry reactor and a gas bubbling reactor, mixing hot liquid slag with CO2 off-gas, to produce solid calcium and magnesium carbonates. The process was found to have the potential to sequester 6% to 11% of CO2 emissions from integrated mills and 35% to 45% of CO2 from electric arc furnaces—apparently not a promising enough result to bring in new research money for phase two.

Sequestration projects have received major support outside the United States, however. Andrew Roden, head of project analysis and development for the Global Carbon Capture and Sequestration Institute in Australia, cites eight projects in various stages of development around the world.

Two are close to realization, Roden says. Ultra-Low Carbon Dioxide Steelmaking, or ULCOS, a consortium of 48 European companies, is in advanced planning for a demonstration project in Florange, France. The goal is to capture 500,000 tons of carbon dioxide annually for pipeline transport to a deep geological saline formation.” The project, 40% European Union funded, should be in operation in 2015.

Emirates Steel in Abu Dhabi plans a capture program for 800,000 tons a year by 2014. Masdar, the Abu Dhabi government's renewable and alternative energy research operation, says CO2 will be transported by pipeline and “injected into [Abu Dhabi's] oil reservoirs for enhanced oil recovery.” The CCS operation will take CO2 from a gas-fired power plant, an aluminum smelter and a steel mill.

Objections and Solutions

“Carbon sequestration is a long shot,” Kavanaugh says. “The big problem is: We know how to capture carbon dioxide, but what do you do with it then?” The supply of CO2 vastly exceeds potential industrial uses. “There's just no need for that much baking soda,” says Kavanaugh.

Energy requirements for these processes may be prohibitive. “One of these technologies uses up to a third of the energy load of the power plant used to run the capture and sequestration process,” Kavanaugh says. “That's a parasitic energy loss.” AISI also perceives significant legal problems in sequestration solutions should stored CO2 escape.

Roden, from the Global Carbon Capture and Sequestration Institute, says these objections aren't new. “Do we just give up and fall on our sword and say it is too hard?” he asks. “Fossil fuel use is increasing globally each year at around 3%. Coal, oil, gas will be with us for a while. The U.S. is a huge emitter of CO2, and the steel industry is a key contributor. The challenge is global. It's critical and we need CCS to work.”

Perhaps, but don't rule out technologies that remove carbon from the steel production process. One such project, now considered a realistic alternative because of urgency to reduce greenhouse gases, involves molten oxide electrolysis, the process used to make aluminum.

The idea, says Massachusetts Institute of Technology (MIT) professor Donald R. Sadoway, is to feed iron ore into a super-heated melt of various oxides (the project has been working with calcium, aluminum and magnesium oxides) in an electrified cell to convert it to pure iron, which accumulates in a pool.

“Periodically you either siphon the iron off at the top or tap it out at the bottom,” Sadoway says. The electrical current produced by the action between anode and cathode keeps the brew bubbling at about 1,600 degrees Celsius, with no external source of heat, Sadoway says.

The end products are oxygen and a remarkably pure iron. “What comes out of a blast furnace or an electrical arc furnace has impurities,” Sadoway says. “We won't have any of those.” The iron is so free of carbon that it will require “doping”—insertion of small amounts of pure carbon—during the final steelmaking phase.

The next phase is to build a scaled-up, pre-pilot cell that, when it's up and running, will operate continuously, producing about 160 pounds of iron and 70 pounds of oxygen a day. After finding an inexpensive anode material, researchers want to make the process work on an enlarged scale. “No one has ever built something like this before,” Sadoway says. “We don't know what the scaling laws are when it's scaled up by a factor of roughly 50 or 100.”

Another project, at the University of Utah, uses hydrogen to reduce iron ore to pure iron. Steelmakers are already using direct-reduction techniques, developed by steel technology firms Midrex and Tenova HYL with natural gas as a reducing agent. These facilities “crack” the gas under high temperatures to separate out hydrogen, which can then strip the oxygen in iron ore's ferrous oxide while producing water and carbon dioxide as emissions. By using pure hydrogen, however, the Utah project hopes to eliminate carbon from the process.

For the moment, the experimental reactor developed by chief researcher Hong Yong Sohn has been adapted to use either pure hydrogen, natural gas or “syngas” (a coal gasification or waste-to-energy product, with limited energy density).

The process is carried out in a suspension or flash type of oven. A granular form of iron ore—mostly from taconite, a powdery low-grade ore from the Upper Midwest, which has been put through a grinding “beneficiation” process—is sprayed directly into a reactor where it mixes with heated gas. “The spray gives it an extremely large surface area, so the reaction is very fast,” Sohn says. “We had to prove that iron oxide particles could be reduced in no more than 10 seconds.” So far, direct reduction occurs in eight seconds or less.

Of course, the speed of the process significantly reduces the amount of required energy. The project has already demonstrated that, when hydrogen is the reduction agent, there's a 38% energy savings over a blast furnace, with only 4% of the carbon dioxide produced.

While suspension ovens have routinely been used to make copper and nickel, they had not been proven as iron reduction reactors until the Utah project. Sohn's research group has shown that at 1,300 degrees Celsius, up to 99% reduction can be achieved within a few seconds.

After another year or two of bench tests, researchers and participating steelmakers will build a pilot test facility that can turn out 50,000 to 100,000 tons of pure iron a year. Like the MIT project, the carbon-free iron produced by the reactor will require a dose of pure carbon in the final steelmaking step.

Both Sohn and Sadoway say their innovative steelmaking techniques should be available for industrial use in the 2020s.