Researchers at the University of Birmingham have developed a process that they say can reduce iron and steelmaking emissions by 90 per cent.
Researchers at the University of Birmingham have designed a new adaptation that can be applied to existing iron and steel furnaces, with the potential to reduce carbon dioxide emissions from the steelmaking industry by nearly 90 per cent.
The research team achieved this through a “closed loop carbon recycling system,” which, according to the university, can replace 90 per cent of the coke that is typically used in modern blast furnace systems. According to the research paper published in the Journal of Cleaner Production, the system produces oxygen as a byproduct.
“Current proposals for decarbonising the steel sector rely on phasing out existing plants and introducing electric arc furnaces powered by renewable electricity. However, an electric arc furnace plant can cost over £1 billion to build, which makes this switch economically unfeasible in the time remaining to meet the Paris Climate Agreement. The system we are proposing can be retrofitted to existing plants, which reduces the risk of stranded assets, and both the reduction in CO2, and the cost savings, are seen immediately,” said Yulong Dil, corresponding author of the research paper, in a press statement.
Most of the world’s steel is produced using blast furnaces that can produce iron from iron ore, and basic oxygen furnaces which then turn it into iron, according to the University of Birmingham. The manufacturing process is very carbon-intensive. In order to make the metallurgical coke used in the process, coal has to be destructively distilled in a coke oven—a process that produces carbon monoxide and carbon dioxide.
With the new carbon recycling system, the researchers envisage capturing the carbon dioxide from the “top gas” that comes out of the furnace and reducing it to carbon monoxide using a “perovskite material.” This carbon monoxide can be fed back into the furnace to raise its air blast temperature.
This is possible because in an environment with a high concentration of carbon dioxide, the perovskite splits the carbon dioxide, which can be fed back into the furnace, and oxygen, which is absorbed by the material. The perovskite can then be returned to its original form using a reaction that takes place in low-oxygen environments. The extra oxygen produced in this process can then be used in the basic oxygen furnace to produce steel.