Context: A recent study by German researchers suggests that hydrogen could be used for steelmaking instead of Carbon.
What is steel?
Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Strong steel consists of a tiny amount – less than 1% – of carbon.
Issues with the current method of steelmaking:
The current method of steelmaking— the blast furnace/basic oxygen furnace route, and the electric arc furnace route—contributes to 5-7% of global emissions. Making one tonne of steel releases 1.8 tonnes of carbon dioxide
|Traditional Steelmaking Process||New Steelmaking Process Using Hydrogen|
|Iron oxide is heated with coke (coal with high carbon content) at 1,700°C inside a blast furnace.||Iron oxide is reacted with hydrogen in a direct reduction reactor.|
|Carbon reacts with oxygen to form carbon dioxide, leaving iron with around 4% carbon behind.||Hydrogen reacts with oxygen in iron oxide, producing water vapour as a byproduct.|
|Iron is remelted and oxygen is blown through it, producing more carbon dioxide and reducing the amount of carbon in the iron to a desirable level.||Creating a “microfracture structure” on the iron oxide feedstock to encourage the creation of channels that drain trapped water and allow hydrogen to replace it in the reaction.|
Thus, the new process releases significantly less Green House gas.
India is the world’s second-largest steelmaker, having produced 118.2 million tonnes in 2021.