Cleaning Up Steel Production

 

              Steel surrounds us in our daily lives; we use this alloy of iron, carbon, and other elements in cars, fridges, surgical instruments, and an incredible number of other products. However, for every ton of steel produced, nearly 2 tons of carbon dioxide are emitted and the extreme demand for steel has resulted in this process accounting for about 8 percent of global carbon dioxide emissions in 2018. This has resulted in many scientists striving for the decarbonization of steel through a couple different approaches.

One approach the scientists have been considering includes the use of hydrogen as a fuel source in order to heat the enormous blast furnaces and executives of steel plants indicate this may be the best solution in the future. Traditionally, this process has utilized liquid natural gas or coke, a derivative of coal, however, these conventional sources lead to the emission of significant amounts of carbon dioxide. Employing hydrogen as a fuel source would release only water as a by-product and would therefore be significantly more environmentally friendly. Unfortunately, the current sources of hydrogen include natural gas reforming and electrolysis, both of which employ fossil fuels as either feedstock or fuel and emit greenhouse gases. If hydrogen could be produced by electrolysis coupled to renewable energy sources such as solar or wind, this could provide a significantly more environmentally friendly avenue to steel synthesis.

Another potential solution suggested by experts includes the use of electric arc furnaces connected to sources of renewable power. Electric arc furnaces themselves are cleaner than the traditional blast furnaces as they do not require the continuous input of coke. Additionally, it is easier to control their internal temperature which increases their efficiency. Connecting these cleaner furnaces to renewable energy sources could allow for the production of low-carbon steel, thereby significantly decreasing the harmful emissions conventionally released.

            The final solution that is being suggested is using bacteria to transform carbon dioxide from the plant exhaust into ethanol. The biotech start-up LanzaTech identified this, or a similar bacterium, in the gut of rabbits that was able to produce ethanol through a process of gas fermentation. With ethanol constituting 10% of every gallon of gasoline sold in the US, this new supply of ethanol would allow for the crops (namely sugar cane, corn, or grasses) that generally provide this compound or the land that these crops grow on to be put to other uses. The fuel produced by these bacteria could be utilized by cars or jets, but it could also be converted to ethylene and then to polyethylene for use in plastic products, therefore allowing for a greener source of plastic. Overall, the implementation of these bacteria would also reduce carbon dioxide emissions and allow for a greener steel production process overall.

References:

https://www.nytimes.com/2021/03/17/business/steel-emissions-arcelor-mittal.html

https://www.mckinsey.com/industries/metals-and-mining/our-insights/decarbonization-challenge-for-steel#

https://www.worldsteel.org/about-steel.html

https://www.energy.gov/eere/fuelcells/hydrogen-fuel-basics#:~:text=Hydrogen%20is%20a%20clean%20fuel,fuel%20cell%2C%20produces%20only%20water.&text=Today%2C%20hydrogen%20fuel%20can%20be,solar%2Ddriven%20and%20biological%20processes

https://www.mbrashem.com/electric-arc-furnaces-vs-blast-furnaces/

https://www.en-former.com/en/hydrogen-revolution-steel-production/

https://www.cnbc.com/2018/07/27/lanzatech-turns-carbon-waste-into-ethanol-to-one-day-power-planes-cars.html

https://en.sysbiotech.at/articles/ralstonia-eutropha-soil-bacteria-with-big-potential/