Manufacturing steel by today’s steelmaking process produces CO2 as a by-product. CO2 is one of the major GHG identified as contributing to climate change. On average 1.2 tons of CO2 was emitted in 2009 for every ton of steel produced in the US. Today, the American steel industry operates with the lowest average energy consumption per ton of steel produced. Because of the close relationship between energy use and GHG emissions, the industry aggregate CO2 emissions per ton of steel shipped were reduced by approximately 35 percent since 1990.
Because of industry’s voluntary investments in R&D and resulting new technology, US steelmaking processes are highly optimized, and efforts will be made continue to achieve incremental improvements. However, in order to make major reductions in future energy/CO2 reductions, new methods of making steel will require completely fresh and innovative thinking.
The North American steel industry has been actively investing in research and development into new transformational processes for making steel that will dramatically reduce or eliminate CO2 emissions. This R&D is called the AISI CO2 Breakthrough Program.
An example is the current program with Massachusetts Institute of Technology to produce iron by molten oxide electrolysis (MOE), an extreme form of molten salt electrolysis, a technology that has been producing tonnage metal for over 100 years – aluminum is produced in this manner. A second project [Ironmaking by] “Hydrogen Flash Smelting," now being conducted at the University of Utah, replaces coke as a blast furnace fuel with hydrogen, natural gas, coal or a combination, could eventually replace the blast furnace and other carbon-based iron making processes that generate large amounts of CO2. Both projects represent significant [long-term] steps towards carbon-free ironmaking, since both will have near-zero CO2 emissions if successful.
In the near term, AISI members with joint funding from the US Department of Energy (DOE) are developing the Paired Straight Hearth Furnace, a high-productivity, low-energy ironmaking unit that can process steel plant wastes, as well as virgin iron materials. Using coal instead of coke, this type of furnace will be available for commercial demonstration in less than five years and will potentially achieve a significant reduction in energy use compared to current technologies.
Additionally, AISI’s Committee on Manufacturing Technology has identified workable carbon capture technologies that can potentially be adapted from the power sector to steel. The key is the “sequestration” part of CCS. As technologies and infrastructure to inject CO2 into the ground are facing serious hurdles, COMT is seeking research proposals this fall to take an industrial CO2 stream and manufacture a co-product.