The following story is an excerpt of an article published in Industrial Heating.
The blast furnaces used today in the United States are similar in form and function to those built about 260 years ago, but the energy efficiency is incomparably better. Through steady engineering improvements, the smelting process has become nearly 20 times more energy-efficient since the mid-1700s. The challenge now is to better understand how to use alternative fuel sources in order to continue to decrease the carbon intensity of blast-furnace ironmaking.
“In ironmaking, there is an immovable baseline of energy that will always need to be supplied for the process to work. To make the process more energy-efficient, we are up against the laws of nature—a hard battle to win” explains P. Chris Pistorius, professor of materials science and engineering and director of the Center for Iron and Steelmaking Research.
By focusing on introducing natural gas into the process, we can prevent the creation of billions of tons of carbon emissions a year.P. Chris Pistorius, Director, Center for Iron and Steelmaking Research, Carnegie Mellon University
“By focusing on introducing a lower-cost, lower-carbon fuel such as natural gas into the process, however, we can prevent the creation of billions of tons of carbon emissions a year.”
Pistorius’ group is focused on studying how best to introduce natural gas into the blast-furnace ironmaking process, comparing coke replacement ratios, carbon intensity and furnace productivity. Just this past fall, the group uncovered new data around the best natural gas utilization methods. They now have better estimates of how much natural gas can be injected through the tuyères, or nozzles in the furnace.
(Left) The Carrie Furnaces (Rankin, PA) circa 1950. Pictured here are Carrie Furnaces #3 and #4 in the foreground, Baltimore and Ohio RR (with trains on tracks) and the Pittsburgh and Lake Erie RR tracks. Employee cars are parked on Braddock Field Plank Road/2nd Avenue Extension. (Photo courtesy Rivers of Steel National Heritage).
(Right) Example of a modern-day blast furnace. This is #14 blast furnace at U.S. Steel Corporation’s Gary Works in Gary, Ind. (Photo courtesy United States Steel Corporation).